Total Reducing Sugar Content Research Articles

Pretreatment of sugarcane bagasse with dilute citric acid and enzymatic hydrolysis: Use of black liquor and solid fraction for biogas production

This study evaluated the pretreatment of sugarcane bagasse (SCB) with dilute citric acid solution for biogas production. The black liquor (BL) from pretreatment and residual solid fraction (RSF) obtained after enzymatic hydrolysis were used as substrates for the biogas production. After saccharifications of the pretreated solid fractions performed with Cellic® CTec 3 cocktail, the highest concentration of total reducing sugars (TRS) was in the range of 10.7–184.8 g L−1 and the sugar yields were in the range of 3.5–88.8%. For BL, the contents of glucose, xylose, and arabinose were in the range of 1.9–8.9 g L−1, 4.0–24.7 g L−1, and 0.2–5.4 g L−1, respectively. Biogas production from BL and RSF resulted, respectively, in maximum values of 563.6 and 57.8 NmL gCOD−1, indicating the feasibility of using dilute citric acid pretreatment coupled to biogas production in biorefineries. Brief energy and economic assessment were carried out considering the energy balance (thermal energy generated by burning biogas - thermal energy spent in the pretreatment), as well as revenue from a possible sale of electricity generated in a combined heat and power system.

Evolution of Physicochemical Parameters during the Thermal-Based Production of Água-mel, a Traditional Portuguese Honey-Related Food Product.

The purpose of this work was to investigate the physicochemical changes occurring during the thermal-based production of água-mel, a traditional Portuguese honey-related food product. The refractive index, color parameters (hue angle, H°; chroma, C*), and the content of total reducing sugars, glucose, fructose, total brown pigments, and 5-hydroxymethylfurfural were monitored along the entire production process, and their evolution was kinetically modelled. Thermal processing caused a gradual decrease in sugars, which was accompanied by the formation of brown pigments and 5-hydroxymethylfurfural, increased concentration of soluble solids as evaluated through refractive index measurements, as well as the appearance of darker colors. In particular, a zero-order kinetic model could explain the changes in H° and reducing sugars, while the evolution of refractive index, brown pigments, 5-hydroxymethylfurfural, C*, fructose, and glucose were best fitted using a first-order kinetics model.

Anaerobic biobutanol production from black strap molasses using Clostridium acetobutylicum MTCC11274: Media engineering and kinetic analysis

Microbial reduction of black strap molasses (BSM) by Clostridium acetobutylicum MTCC 11,274 was performed for the production of biobutanol. The optimum fermentation conditions were predicted using one factor at a time (OFAT) method. The identification of significant parameters was performed using Plackett-Burman Design (PBD). Furthermore the fermentation conditions were optimized using central composite design (CCD). The kinetics of substrate utilization and product formation were investigated. Initial pH, yeast extract concentration (g/L) and total reducing sugar concentration (g/L) were found as significant parameters affecting butanol production using C. acetobutylicum MTCC11274. The maximum butanol production under optimal condition was 10.27 + 0.82 g/L after 24 h. The waste black strap molasses obtained from sugar industry could be used as promising substrate for the production of next generation biofuel.

Large scale production of succinic acid by fermentation of sequential inorganic salt pretreated oil palm empty fruit bunch

The abundance of accumulated oil palm wastes has led to their usage as substrate in the production of organic acid such as succinic acid (SA). For the first time, oil palm empty fruit bunch (OPEFB) which was pretreated using inorganic salts was utilized for SA production in a large-scale fermenter. OPEFB was pretreated sequentially using 15% (w/v) Na3PO4.12H2O and 5% (w/v) ZnCl2 solution before undergoing fermentation process in a 16 L bioreactor in the presence of Actinobacillus succinogenes ATCC 55618. The optimum fermentation conditions were adopted from small-scale setting and implemented in the large-scale setting. Two different fermentation approaches were studied; simultaneous saccharification and fermentation (SSF) and modified simultaneous saccharification and fermentation (mSSF). This research revealed that mSSF produced higher concentration of total reducing sugars (TRS) yield and SA compared to the SSF method. SSF of inorganic salts pretreated OPEFB produced maximum SA concentration (38.85 gL-1) and yield (0.39 gg-1). Meanwhile highest TRS yield obtained from pre-hydrolysis was 0.79 gg-1 at 72 h and SA (50.5 gL-1) was acquired under the mSSF at 132 h. Therefore, mSSF is a novel process that has propitious potential for SA production in a large-scale setting which can be further executed in the industrial scale.

Mathematical Modelling of Alkaline and Ionic Liquid Pretreated Coconut Husk Enzymatic Hydrolysis

The problem of crude oil reserve shortage and air quality decline currently have led researches on renewable fuel such as bioethanol and biohydrogen. The attempt to provide such biofuel involves the utilization of enormously available wasted materials, lignocellulose. Coconut husk is one of such materials available in Indonesia. The previous work had reported the quantity of total reducing sugar produced after the enzymatic hydrolysis of pretreated coconut husk. The pretreatment methods used were dilute sodium hydroxide solution (1 and 4% w/v), 1,3-methylmethylimidazolium dimethyl phosphate ionic liquid and the combination of both methods. This work focused on constructing the mathematical model which describes the kinetic of those enzymatic hydrolysis reactions. Mathematical model expressions help describing as well as predicting the process behavior, which is commonly needed in the process design and control. The development of mathematical model in this work was done based on the total reducing sugar concentration resulted in batch hydrolysis reaction. The kinetic parameters including initial available substrate (S0), maximum reaction rate (rmax), and half-maximum rate constant (KM). According to the values of half-maximum rate constant (KM), the enzymatic hydrolysis performance of coconut husk treated using ionic liquid is better than that treated using dilute alkaline solution as the former had shown lower KM value and hence higher enzyme affinity to the substrate. The best hydrolysis result was performed using combination of 1% dilute sodium hydroxide solution and ionic liquid with kinetic model parameter of 0.5524 g/L.h of rmax, 0.0409 g/L of KM, and 4.1919 g/L of S0. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Investigation of the Effects of Worm Fertilizer on the Yield and Quality of Tobacco

Tobacco which still has a great economic importance in the world and Turkey provides extensive employment opportunities from growing to evaluation stage to a certain part of our people and is produced as a family enterprise for centuries in our various regions. The aim of the study was to determine in the effects of worm fertilizer on Aegean type tobacco yield and some quality parameters. The search was carried out in a farmer field in Saruhanli district of Manisa province in 2019. Saribaglar-407 type tobacco was used as a research material. Experimental design was Randomized Complete Parcel Design with three replications. In this research, plant height (cm), number of the leaves (per/plant), cured leaf yield (kg ha-1), tobacco visual quality, leaf priming position (%), total alkaloid (nicotine) (%), total reducing sugar (%) and chlorine (%) were determined. Plant height, number of the leaves, yield, nicotine, total reducing sugar and chlorine contents were found 126.7 cm, 48 per/plant, 141 kg ha-1, 1.02%, 9.08% and 0.48%, respectively. An increase in the middle stalk position of the plant was recorded with the application of fertilizer and the results were obtained among the appropriate values for tobacco of the Aegean region in terms of chemical composition.
 Keywords: tobacco, worm fertilizer, yield, nicotine.

A preliminary investigation of caramelisation and isomerisation of allulose at medium temperatures and alkaline pHs: a comparison study with other monosaccharides

SummaryAllulose, also known as rare sugar, is a very reactive monosaccharide in browning reactions. In this study, the caramelisation of allulose was investigated for the first time. To study caramelisation, sugar solutions (glucose, fructose and allulose) were prepared with distilled water and buffer solutions at pH 7, 10, 12 and were freeze‐dried afterwards. To let caramelisation occur, samples were incubated at 55% relative humidity (RH) and 50 °C. Results showed that samples prepared with pH 10 and pH 12 buffer solutions resulted in a higher browning rate than samples prepared with distilled water (DW) and pH 7 buffer solution. Moreover, according to HPLC and total reducing sugar content results, allulose (Allu) samples had the lowest remaining reducing sugar (RRS) amount, indicating that Allu samples depleted more in the reaction. Overall, the approach followed in this study can be considered as a novel strategy to obtain allulose‐containing caramel‐like products more efficiently than conventional methods.

Valorization of Lignocellulosic Wastes to Produce Phytase and Cellulolytic Enzymes from a Thermophilic Fungus, Thermoascus aurantiacus SL16W, under Semi-Solid State Fermentation.

Agricultural wastes are lignocellulosic biomasses that contain high mineral and nutrient contents. This waste can be used as a raw material in industrial enzyme production by microbial fermentation. Phytase is an important enzyme used in animal feed to enhance the amount of phosphorus available for the growth and overall health improvement of monogastric animals. Fungi offer high potential as an effective source in the production of various extracellular enzymes. In this study, the production of lignocellulolytic enzymes (endoglucanase and xylanase) and phytase by a thermophilic fungus, namely Thermoascus aurantiacus strain SL16W, was evaluated using sixteen different Thai agricultural forms of waste under conditions of high temperature (45 °C). Semi-solid state fermentation was used in the production experiments. The results of this study reveal that the highest phytase activity (58.6 U/g substrate) was found in rice bran, whereas the highest degrees of activity of endoglucanase and xylanase were observed in wheat bran and red tea leaves at 19 and 162 U/g substrate, respectively. Consequently, the optimal conditions for phytase production of this fungus using rice bran were investigated. The results indicate that the highest phytase yield (58.6 to 84.1 U/g substrate) was observed in rice bran containing 0.5% ammonium sulfate as a nitrogen source with 10 discs of inoculum size at a cultivation period of 9 days at 45 °C and moisture content of 95%. Notably, the phytase yield increased by 1.71-fold, while endoglucanase and xylanase were also increased by 1.69- and 1.12-fold, respectively. Furthermore, the crude enzyme obtained from the optimal condition was extracted. The crude enzyme extract was then separately added to red tea leaves, rice straw, corncobs, palm residue, and peanut husks. Subsequently, total reducing sugar and phosphorus contents were determined. The results indicate that the highest level of reducing sugar (122.6 mg/L) and phosphorus content (452.6 mg/L) (p < 0.05) were obtained in palm residue at 36 and 48 h, respectively, after the addition of the crude enzyme extract. This study has provided valuable information on a potentially eco-friendly way to valorize agricultural waste into value-added products as industrial enzymes.

Production of Hemicellulolytic Enzymes by a Novel Trichoderma koningiopsis 2OI2A1M and Its Application in the Saccharification of Barley Bagasse

This study aims to investigate the ability of the fungus Trichoderma koningiopsis 2OI2A1M to produce enzymes that act in the depolymerization of the lignocellulosic biomass of agro-industrial by-products and its application in the saccharification of barley bagasse. The production of xylanase by the fungus T. koningiopsis 2OI2A1M using the barley bagasse provided the highest activity (53.6 U/mL). The CMCase activity was obtained with carboxymethylcellulose (2.1 U/mL). Among the best inducers for β-xylosidases were sugarcane bagasse (11.8 U/mL) and for β-glucosidases were carboxymethylcellulose (36.4 U/mL) grown for 120 h in submerged culture. The higher production of fermentable sugars from the enzymatic saccharification of in natura barley bagasse, yielded a concentration of total reducing sugars (10.7%), glucose (5.9%) and xylose (1.6%) after 24 h. The comparative analysis of the morphological structure of the barley bagasse by scanning electron microscopy demonstrated that the simultaneous action of T. koningiopsis 2OI2A1M enzymes does not require previous structural modifications in the barley bagasse for effectiveness in the saccharification process. Thus, barley bagasse is a candidate for a sustainable alternative to produce fermentable sugars, a primary focus in the production of second-generation fuels.

Farro 57 Rice Cultivar: A Comparative Study of the Nutritional Composition of its Parboiled Milled Rice, Brown Rice and Germinated Brown Rice

This work analyzed the nutritional composition of germinated brown rice (GBR) produced from FARRO 57 rice cultivar and compared it with that of ungerminated brown rice (UBR) and ungerminated parboiled milled/white rice (UWR) from the same cultivar which were used as controls. The aim was to evaluate and compare the nutritional composition of UBR, UWR and GBR of the rice cultivar. The experimental design used was a completely randomized design. GBR was produced by soaking brown rice grains in distilled water for 24 h and then made to germinate in a laboratory incubator at 35° C for 12, 24 and 36 h. The parameters determined included proximate composition, energy value, minerals, vitamins, total starch, amylose and total reducing sugar contents and they were determined in triplicates. It was found that GBR had significantly higher contents of protein (14.54-15.01%), ash (3.36.98%), total dietary fibre (9.23-9.31), phosphorus (130.55-187.15 mg/100 g), iron (6.22-9.94 mg/100 g), calcium (455.0-560.0 mg/100 g), zinc (2.51-2.72 mg/100 g), selenium (92.10-107.50 µg/100 g), vitamin B2 (2.35-2.92 mg/100 g) and vitamin E (1.82-2.68 mg/100g) than UBR and UWR. Furthermore, there was no significant difference between the contents of vitamins A (19.45-19.72 IU), B1 (0.33-0.34 mg/100g) and B6 (1.00-1.10 mg/100g) of GBR and UBR samples, however they were all significantly higher than that of UWR. The GBR also had significantly lower amount of total carbohydrate (64.21-71.09%), total starch (54.91-60.92%), amylose (22.05-28.14%), and total reducing sugar (5.14-11.23%) than UBR and UWR. Amongst the GBR samples, the ash, protein, and the minerals increased with increase in duration of germination while the total carbohydrate, starch and amylose decreased with increase in duration of germination. GBR was recommended over UBR and UWR due to its optimum levels of the nutrients.

Comparative study of the efficiency of pretreatment with alkaline hydrogen peroxide in pineapple bagasse in different granulometries submitted to acid and enzymatic saccharification

This work had the purpose of evaluating the efficiency of the pretreatment with alkaline hydrogen peroxide of pineapple bagasse in order to obtain fermentable sugars by applying acid and enzymatic hydrolysis to said residue. Four experimental designs were applied to study the best conditions for the pre-treatment. Total reducing sugars (TRS) concentration was the response and hydrogen peroxide concentration, time and temperature were the independent variables. The studies were conducted using pineapple bagasse with particle sizes of 20 mesh and 48 mesh. Acid saccharification, with 2.9% sulfuric acid (v/v), following the pre-treatment, yielded TRS concentrations that reached 0.094 g of TRS/g of raw bagasse for 20 mesh and 0.101 g of TRS/g of raw bagasse for 48 mesh. The enzymatic saccharification, with 9 FPU/g cellulase and 2% (m/v) of bagasse, reached 0.063 g of TRS/g of raw bagasse for both particle sizes. The peroxide concentration showed a significant influence, the use of high concentrations reduced the TRS output in both hydrolysis. With the results found in this work, it is possible to infer the feasibility of applying pineapple bagasse as a lignocellulosic raw material.

Quality authentication and geographical origin classification of honey of Amhara region, Ethiopia based on physicochemical parameters

The knowledge of the physicochemical properties of honey from different botanical and geographical origins is important to identify the honey with better quality. Accordingly, the Amhara region of Ethiopia is producing honey of different quality for the local and export market. Thus, the study was aimed at estimating the quality and developing a chemometric model for geographical origin classification of the region’s honey based on its physicochemical parameters. A total of 47 honey samples were collected from 7 administrative zones (East Gojjam, West Gojjam, Awi, South Gondar, South Wollo, North Wollo and Wag Himera zones) of three major provinces (Gojjam, Gondar and Wollo) of the region. Eight physicochemical parameters of the honey samples were determined using internationally accepted standard methods. In view of that, the average values of the studied physicochemical parameters at each administrative zone were in the range of 16.06–18.51, 0.26–0.60, 61.45–71.41 and 2.96–4.73 g/100 g of honey for moisture content, ash content, total reducing sugar and apparent sucrose content respectively. In addition, pH (3.85–4.23), free acidity (26.39–37.80 meq/kg), electrical conductivity (33.37–63.43 μS/cm) and HMF (3.88–8.50 mg/kg) were determined in the studied samples. Based on these values the region’s honey was in a good quality that meets the national and international standard limits. In the PCA model, the first three principal components explained about 69.14% of the total variations and the LDA model had an average of 80.85% discrimination power. The LDA model was checked by cross-validation method and 100% of samples in the validation set were correctly classified by the model.

Lipid bioproduction from delignified native grass (Cyperus distans) hydrolysate by Yarrowia lipolytica

In the present study, native grass (Cyperus distans) was utilized for the production of lipid using Yarrowia lipolytica MTCC 9519. Initially, pretreatment methods using hydrothermal and alkaline delignification were performed to obtain cellulose rich liquid fractions. Delignified native grass biomass was enzymatically hydrolyzed to convert non fermentable sugars in to fermentable sugars. The growth of Y. lipolytica MTCC 9519 by utilizing pretreated native grass hydrolysate was evaluated. The yield and concentration of total reducing sugars after enzyme hydrolysis were found to be 378 ± 35 mg/g of pretreated biomass and 28.64 g/L ± 1.25 g/L, respectively. When pretreated, delignified native grass hydrolysate was used with (NH4)2SO4 (30C/N ratio) and sodium n-octanoate (0.4% w/w), the dry cell weight and lipid accumulation of Y. lipolytica MTCC 9519 reached about 19.88 ± 1.54 g/L and 53.62% (w/w) respectively after 96 h. Thus, native grass could become a promising substrate for biolipid production.

Physicochemical, antioxidant and FTIR-ATR spectroscopy evaluation of Kashmiri honeys as food quality traceability and Himalayan brand.

Three types of honeys viz. Robinia pseudoacacia (RSA), Plectranthus rugosus (PR) and multifloral honey (MF) from Kashmir Himalayas of India were characterized on the basis of physicochemical, antioxidant and FTIR-ATR spectroscopic features. The physicochemical parameters indicated that ash content, electrical conductivity, redness (a*) and yellowness (b*) were higher in MF honey, moisture content, Hydroxymethylfurfural (HMF) and lightness (L*) in PR honey and Water activity (aw) and proline content in RSA honey (P ≤ 0.05). Significantly higher values of total sugar, total reducing sugar and sucrose content was observed in MF honey (P ≤ 0.05). The total phenolic content (TPC), total flavonoids, ferric reducing antioxidant power and 1, 1-diphenyl-2-picrylhydrazy-IC50 (DPPH- IC50) free radical scavenging activity showed that MF honey had significantly higher antioxidant activity (P ≤ 0.05). ATR-FTIR analysis demonstrated that the absence of peaks at broad band around 1653.454-1637.656cm-1 in MF honey, 1185.989-1153.072cm-1 and 918.570-916.544cm-1 wavenumbers in PR honey thus clearly discriminating different types of honeys. The results revealed that physico-chemical, antioxidant and spectroscopic characteristics of honey types vary with geographic origin and their floral sources and MF honey have a high therapeutic potential.

Physicochemical Quality of Honey Samples Collected from Chena District, Southwestern Ethiopia

The objective of this study was to determine physicochemical properties (color, moisture, ash, pH, free acidity, HMF, reducing sugars, sucrose and electrical conductivity) of honey produced in Chena district, Southwestern Ethiopia. Nine (9) honey samples each of 0.5 to 1kg were obtained from Chena district. Moisture and ash content were determined by AOAC method. pH was determined by digital pH meter. HMF and honey color were determined by using spectrophotometer. The free acidity was quantified by titration method. Total reducing sugar and sucrose contents were determined by Lane and Enyon method. There was significant variation (p < 0.05) observed between honey samples. The result revealed that S2 and S6 honey samples contained the highest ash (0.3 ± 0.02 and 0.3 ± 0.04 g/100g, respectively), free acidity (39 ± 1.4 and 41 ± 1.4 meq/kg, respectively) and electrical conductivity (0.68 ± 0.08 and 0.67 ± 0.04 mS/cm, respectively) than other honey samples. The honey samples S7 and S8 had highest moisture content (22.5 ± 1.4 and 21.2 ± 1.7 g/100g, respectively) and honey color (124 ± 0.5 and 123 ± 2.1 mm Pfund scale, respectively) than other honey samples. The honey sample S5 (4 ± 0.2), S6 (4 ± 0.2), and S9 (4.2 ± 0.4) had highest pH value. In addition, the result showed that S9 contained highest HMF content (17.1 ± 2 mg/kg). Furthermore, honey sample S1 (69.7 ± 1 g/100g) and S4 (70.2 ± 1) contained the highest total reducing sugar. Finally, the result showed that honey sample S8 had highest sucrose content (5.17 ± 0.8 g/100g). Results obtained in this study, indicated that tested honey samples produced in Chena district are good for national as well as international market. More research should be conducted on the storage effect of honey to evaluate its safety for human consumption.

Study of the autonomous process of inversion of sugarose through thermal influence at ultrasonic processing of vegetable and fruit pures

Relevance. The article presents the results of a study of the increase in the amount of reducing sugars in the inversion of sucrose due only to thermal effects during ultrasonic processing of vegetable and fruit monocomponent purees (with or without added sucrose). The relevance of the study is to identify the quantitative thermal component of a separate process in the total inversion of sucrose at the specified parameters of ultrasonic action on the product.Material and methods. to perform this task, experimental samples of carrot, pumpkin and Apple puree with the addition of sucrose in an amount of 5% (by weight) and without it were previously made, which were then subjected to heat treatment at the same temperature and time exposure (at a temperature of 50 °C for 30 minutes). To study the dependence of the degree of sucrose inversion on the component composition of the processed product, the mass fraction of reducing sugars – fructose and glucosewas determined in the manufactured experimental samples of natural fruit and vegetable purees (without added sucrose) and in mixtures of purees with sucrose (according to a given recipe) before and after heat treatment at the specified parameters, depending on the recipe composition and pH of the medium.Results. The obtained results of the study of the carbohydrate composition before and after thermal exposure show that the amount of reducing sugars in products subjected to heat treatment has significantly increased, compared to the initial content. Thus, in Apple puree with added sucrose, the mass fraction of fructose after heat treatment of the mixture increased by 197 mg per 100 g, i.e. by 3.8%, and glucose – by 192 mg per 100 g, i.e. by 6.7%. The total invert sugar content of the Apple mixture increased by 4.8 %. In the carrot mixture of puree with sugar, the content of total reducing sugars after thermal exposure increased by 5.4%. At the same time, in carrot natural puree, the increase in reducing sugars was only 3.6%, which is 1.5 times lower. In the pumpkin puree mixture with sugar, the total content of reducing sugars increased by 3.9%, and in the natural puree, the amount of invert sugars increased by only 2.7%, which is 1.4 times lower than puree with added sugar.

Biological production of hydrogen and acetone- butanol-ethanol from sugarcane bagasse and rice straw using co-culture of Enterobacter aerogenes and Clostridium acetobutylicum

Production of hydrogen and acetone-butanol-ethanol (ABE) from hydrolysates of sugarcane bagasse (SCB) and rice-straw (RS) was carried out via dark fermentation using co-culture of Enterobacter aerogenes and Clostridium acetobutylicum. The best improvement in the yield of hydrogen and total ABE production were observed for alkaline pretreated RS at 100 °C for 60 min obtained from the highest total reducing sugars concentration of 40.7 g L−1 after the enzymatic hydrolysis. The hydrolysates of alkaline pretreated samples at 100 °C were efficiently converted to H2 by co-culture of Enterobacter aerogenes and Clostridium acetobutylicum with the highest hydrogen yield of 136.3 and 149.9 mL H2 g−1-VS of SCB and RS, representing 3.4 and 1.5-fold enhancement in the hydrogen production yield over that obtained from the pure cultures of Enterobacter aerogenes and Clostridium acetobutylicum, respectively. Mass balance and energy generation analysis indicate that the highest specific ABE and total energy production yields per gram untreated feedstock reached 0.12 g ABE and 5.5 kJ for SCB and 0.08 g ABE and 6.6 kJ for RS.

Use of kombucha culture in the production of fermented dairy beverages

Kombucha is a beverage obtained by fermenting tea containing sugar as a result of the symbiotic relationship between yeast and acetic acid bacteria. In this study, milk and various herbal teas (sage, blackberry, and green tea) were mixed in the ratio of 60:40 (v/v) and fermented with kombucha culture. 2.2-Diphenyl-1-picrilhydrazyl (DPPH) radical scavenging activity, total phenolic content, total reducing sugar content, and the microbiological and sensory properties of the fermented dairy beverage were examined. The highest DPPH radical scavenging activity was observed on the 1st day of storage of the blackberry tea-blended fermented beverage (98.48%), and the highest total phenolic content was observed on the 30th day of the green tea-blended fermented beverage (81.51 mg/mL). The maximum amount of glucuronic acid (0.42 g/100 mL) was observed on the 20th day of storage in the sage-blended fermented dairy beverage. The most favorite product was the blackberry blend, whereas the least favorite was the dairy beverage (control sample) fermented with kombucha based on sensory scores. This study demonstrates that milk and herbal teas could be successfully fermented with kombucha culture, thereby improving its functional properties.

Response surface methodology (RSM) for optimization of thermochemical pretreatment method and enzymatic hydrolysis of deodar sawdust (DS) for bioethanol production using separate hydrolysis and co-fermentation (SHCF)

In the present work, Cedrus deodara (deodar) sawdust abbreviated as DS was subjected to thermochemical pretreatment followed by enzymatic hydrolysis and fermentation for bioethanol production. Response surface methodology (RSM) based on central composite design (CCD) tool was employed to optimize dilute acid pretreatment method (at 121 °C temperature and 1-bar pressure) and enzymatic hydrolysis processes. Factorial design of experiments used chemical concentration, incubation time, and biomass loading to optimize thermochemical pretreatment method using dilute acid concentration. Maximum total reducing sugar (TRS) concentration (13.62 g/L) was obtained using optimized conditions (1.5% HCl concentration, 10% biomass loading and 30-min incubation time). These significant studies were subjected to optimize enzymatic hydrolysis process using the CCD tool of the RSM where cellulase loading, xylanase loading, pH, and temperature were taken into consideration. TRS concentration obtained was 29.20 g/L after 48 h with enzyme loading of 9 U/g biomass, each for cellulase and xylanase enzyme at pH 5.0 and 30 °C temperature. Fermentation conditions for enzymatically hydrolyzed DS revealed that at 10% (v/v) yeast inoculum concentrations (Saccharomyces cerevisiae (MTCC-36) and Pichia stipitis (NCIM-3498)) after 24-h fermentation time and pH 5.0, bioethanol concentration was 14.25 g/L with 95.68% conversion efficiency. Characterization studies for native and pretreated DS by Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM) analyses revealed delignification rate of 30.93% of DS biomass under optimized thermochemical pretreatment conditions. Statistical studies for optimization of pretreatment and enzymatic hydrolysis for bioethanol production stated DS sawdust (a furniture industry waste) as a potential substrate for biofuel production.

Variables Affecting Delignification of Corn Wastes Using Urea for Total Reducing Sugars Production.

In this work, a combination of mechanical and chemical pretreatments using urea on corn residues (leaves and stems) was evaluated to obtain total reducing sugars (TRSs). The residues were characterized via high-performance liquid chromatography (HPLC) to quantify biomass composition. During the mechanical pretreatment, the particle size of the biomass was reduced to 0.5, 1, and 2 mm. The chemical pretreatment was performed with urea solution at different concentrations (2, 5, and 10% w/v) and a fixed biomass-to-solvent ratio of 1:25 (g/mL) as well as stirring at 150 rpm for 20 h. The effect of temperature on the pretreatment results was evaluated by varying such operating variables in 30 and 50 °C. After both pretreatments, hydrolysis was carried out in an autoclave using sulfuric acid at 1% v/v at 121 °C for 1 h. The content of TRS was quantified using 3,5-dinitrosalicylic acid (DNS) method and biomass after pretreatment was characterized via Fourier transform infrared (FT-IR). For both leaves and stems, the HPLC technique reported the presence of 47.4 g of cellulose, 40.04 g of hemicellulose, and 26.38 g of lignin. It was found that the highest amount of TRS (36.50 g/L) was obtained with a urea concentration of 2% at 50 °C using a particle size of 0.5 mm. The production of TRS was significantly higher for pretreated biomass than that for raw corn residues, confirming the importance of both mechanical and chemical pretreatments to reach better delignification results.